1. Field of the Invention
The invention relates to a device for detecting the variation of a capacitive impedance, the dielectric of which consists of a lubricant, provided with an oscillator that supplies a signal having a predetermined frequency to the capacitive impedance by way of a bias impedance.
2. Description of the Prior Art
In a known device of this kind, output signals are delivered that provide a measure of the thickness of a lubricant film between surfaces rolling or sliding against each other and of the percentage contact during a definite interval of measurement. Although this known device has the advantage that especially accurate results of measurement are obtained, the known device is comparatively complicated, and costs of manufacture are high. In practice, however, a need is felt for a simple and inexpensive device whereby the lubrication of parts in motion relative to each other and lubricated with a lubricant can be evaluated, and in particular the quality of said lubricant, as, for example, in bearing systems where oil film monitoring is very important.
The present invention, then, intended to provide a device of the kind initially mentioned, satisfying this requirement.